Hi all,
I have some engine problems with my XJR (100tmiles), tried to solved it by myself, but after the diagnostic I need some help..
What says the diagnostic..:
P1601 - this one I really donīt know
P0171 - lean mixture
P0174 - lean mixture
P0133 - Upper O2 sensor
P0153 - Upper O2 sensor
P0400 - EGR valve leakage
Car runs in my opinion normal and I do not see any abnormalities in its behaviour, power or consumption. But..
Engine warning amber light is always on and sometimes also "Restricted performance" appears - then on 3.000rpms rev limiter is acting. I observed that "RP" not everytime but usually appears in the begining of braking by the brakes after longer braking by the engine. After few moments (20sec, sometimes ca. 1km) "RP" warning disappear.

I found that EGR valve was disconnected from the throttle body and screws were missing(!) - I installed new gasket and screws. Also repaired cracked full load breather hose, but all this did not solve the problems.. (after these repairs diagnostic was not provided)
Battery is new, air hoses seems to be airtight.

Any recommendations or possible solutions..?
Thank you very much for your help!
Milos

 

Great car! It looks like you have some ignored maintenance on this car. The two leans codes are more than likely caused by the breather hose and the EGR problem. The EGR code is probably from the EGR problem. The oxygen sensor codes could have happened from the lean codes and the EGR codes. I believe they are all related. I think that all that may have worn the oxygen sensors past the point of repair. I suggest getting a new breather hose and two new upper oxygen sensors. Make sure you can clear the codes. If you don't clear those codes, they will not clear themselves. Let us know how it works out.

 

I second that, they all are related, first, remove and clean the EGR and tubing, replace gasket with a new one.

If you want to clear codes and drive, if CEL comes back on, run OBD2 and see what codes come back. Of the O2 codes come bac, change sensors.

If no, codes good.

 

Thank you for your recommendation!
I also belive that all the DTCs are related, but hope in some trivial solution as O2 sensors or EGR stacked full of mess.
During weekend I will try to clean all the hoses, EGR and TB and will inform you about the situation.

Maybe next question if is it possible to clear DTCs without diagnostic? (workshop is closed during weekend and I am inpatient to see if the amber light will appers again..)

Milos

 

Yes with any OBDII scan tool.

 

So, finally after short brake, I can tell you, that all my problems seems to be solved.
I just changed some cracked hoses and clean EGR valve (and fix it to the TB of course) and all DTCs disappeared..
I hope that this will be for long time all.

Thank you one more time